Aims

During total knee replacement (TKR), surgeons can choose whether or not to resurface the patella, with advantages and disadvantages of each approach. Recently, the National Institute for Health and Care Excellence (NICE) recommended always resurfacing the patella, rather than never doing so. NICE found insufficient evidence on selective resurfacing (surgeon’s decision based on intraoperative findings and symptoms) to make recommendations. If effective, selective resurfacing could result in optimal individualized patient care. This protocol describes a randomized controlled trial to evaluate the clinical and cost-effectiveness of primary TKR with always patellar resurfacing compared to selective patellar resurfacing.

Aims

We compared the risks of re-revision and mortality between two-stage and single-stage revision surgeries among patients with infected primary hip arthroplasty.

Aims

Periprosthetic hip-joint infection is a multifaceted and highly detrimental outcome for patients and clinicians. The incidence of prosthetic joint infection reported within two years of primary hip arthroplasty ranges from 0.8% to 2.1%. Costs of treatment are over five-times greater in people with periprosthetic hip joint infection than in those with no infection. Currently, there are no national evidence-based guidelines for treatment and management of this condition to guide clinical practice or to inform clinical study design. The aim of this study is to develop guidelines based on evidence from the six-year INFection and ORthopaedic Management (INFORM) research programme.

Aims

We compared the risks of re-revision and mortality between two-stage revision surgery and single-stage revision surgery among patients with infected primary knee arthroplasty.

Prosthetic joint infection (PJI) is an uncommon but serious complication of hip replacement. Over 1,000 operations are performed annually in the United Kingdom for PJI following hip replacement, using either one- or two-stage revision arthroplasty. It is unclear which is preferred by patients and which has the best long-term outcome. This qualitative study aims to describe patient experiences of treatment and recovery following one- and two-stage revision arthroplasty for PJI within the context of a pragmatic randomised controlled trial comparing these two approaches. Semi-structured interviews were conducted with 32 patients undergoing one- or two-stage revision treatment for PJI as part of a UK multi-centre randomised controlled trial. Patients were recruited from 12 participating National Health Service (NHS) Orthopaedic Departments and were interviewed 2–4 months after their first revision surgery and again approximately 18 months later. Final sample size was justified on the basis of thematic saturation. All patients consented to the interview being audio-recorded, transcribed, anonymised and analysed using an inductive thematic approach. Ethical approval was provided by NRES Committee South-West Frenchay, 14/SW/116. Patients in both the one- and two-stage treatment groups described prolonged hospital stays, with burdensome antibiotics and brief physiotherapy treatment. However, following discharge home and during recovery, participants undergoing two-stage revision with an ‘empty hip' or with a spacer reported being physically restricted in almost every aspect of their daily life, resulting in inactivity and confinement to home. Mobility aids were not sufficiently available through the health service for these patients. A key difference is that those with a spacer reported more pain than those without. Approximately one year following their second-stage revision, participants described being more independent and active, but two directly attributed muscle weakness to the lengthy period without a hip and described resulting falls or dislocations that had complicated their recovery. In contrast, those undergoing one-stage revision and CUMARS appeared to be more alike, reporting better mobility, functionality and independence, although still limited. Participants in these groups also reported minimal or no pain following their revision. A key difference between CUMARS and one-stage revision was the uncertainty of whether a second operation was necessary, which participants described as “hanging over them”, while those in the two-stage empty hip or spacer group described a more positive anticipation of a second definitive operation as it marked an end to what was described as a detachment from life. Our findings highlight the differences between patient experiences of recovery following revision arthroplasty, and how this is influenced by the surgical approach and presence or lack of spacers. An understanding of lived experiences following one- and two-stage surgical interventions will complement knowledge about the clinical effectiveness of these different types of revision surgery.

Aims

To develop and validate patient-centred algorithms that estimate individual risk of death over the first year after elective joint arthroplasty surgery for osteoarthritis.

The development of an algorithm that provides accurate individualised estimates of revision risk could help patients make informed surgical treatment choices. This requires building a survival model based on fixed and modifiable risk factors that predict outcome at the individual level. Here we compare different survival models for predicting prosthesis survivorship after hip replacement for osteoarthritis using data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man.

In this comparative study we implemented parametric and flexible parametric (FP) methods and random survival forests (RSF). The overall performance of the parametric models was compared using Akaike information criterion (AIC). The preferred parametric model and the RSF algorithm were further compared in terms of the Brier score, concordance index (C index) and calibration.

The dataset contains 327 238 hip replacements for osteoarthritis carried out in England and Wales between 2003 and 2015. The AIC value for the FP model was the lowest. The averages of survival probability estimates were in good agreement with the observed values for the FP model and the RSF algorithm. The integrated Brier score of the FP model and the RSF approach over 10 years were similar: 0.011 (95% confidence interval: 0.011–0.011). The C index of the FP model at 10 years was 59.4% (95% confidence interval: 59.4%–59.4%). This was 56.2% (56.1%–56.3%) for the RSF method.

The FP model outperformed other commonly used survival models across chosen validation criteria. However, it does not provide high discriminatory power at the individual level. Models with more comprehensive risk adjustment may provide additional insights for individual risk.

Patients with knee prosthetic joint infection (PJI) frequently receive one- or two-stage revision. To explore the feasibility of a randomised controlled trial (RCT) comparing methods, we analysed a UK registry, interviewed patients and surgeons, systematically reviewed literature, held a consensus meeting, and assessed progress of an RCT in hip PJI. In 2014, in England and Wales, knee PJI was treated with one- or two-stage procedures in 19% and 71% of patients respectively. Between 2007 and 2014, use of one-stage procedures doubled and, in major centres, up to 42% of treatments were one-stage. We conducted in-depth interviews with 16 patients with knee PJI and 11 surgeons performing one- or two-stage revision. Patients considered randomisation acceptable with appropriate counselling and, depending on infecting organisms and health status, surgeons would randomise treatments. In meta-analysis, two-year re-infection rates in 10 one-stage series (423 patients) and 108 two-stage series (5,129 patients) were 7.6% (95%CI 3.4,13.1) and 8.8% (7.2,10.6) respectively. In a series of patients with knee PJI, surgeons from 2 major centres considered 6/15 patients eligible for either treatment, with 4 more potentially eligible after treatment of soft tissue infection. In an ongoing RCT of surgical treatment of hip PJI, 116 patients have been randomised at 14 centres in 3 years. Randomising patients with PJI is feasible but, as knee PJI is uncommon, a multicentre RCT would be required. Based on WOMAC score outcome and appropriate assumptions on eligibility and acceptability, 170 patients would need to be randomised over 4 years at 14 major centres.

Restoring native hip anatomy and biomechanics is important to create a well-functioning total hip arthroplasty (THA). Hip offset and leg length are regarded as the most important biomechanical characteristics. This study investigated their association with clinical outcomes including patient reported outcome measures (PROMs) and functional tests. This prospective cohort study was conducted in 77 patients undergoing primary THA (age=65±11 years). Hip offset and leg length were measured on anteroposterior radiographs of the hip pre- and postoperatively. Participants completed the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) and performed functional tests (i.e. gait, single leg stance, sit-to-stand, block step-up) preoperatively, and 3 and 12 months postoperatively. A wearable motion sensor was used to derive biomechanical parameters. Associations between radiographic and functional outcomes were investigated with the Spearman's rho correlation coefficient. Subgroup comparisons were conducted for patients with more than 15% decreased or increased femoral offset after THA. Differences in postoperative offset and leg length had little impact on clinical outcomes. Femoral offset subgroups demonstrated no significantly different WOMAC function scores. In functional tests, patients with >15% decreased femoral offset after THA demonstrated more sagittal plane motion during block step-up (14.43° versus 10.66°; p=0.04) while patients with >15% increased femoral after THA demonstrated more asymmetry of frontal plane motion during block step-up (34.05% versus 14.18%; p=0.03). To create a well-functioning THA, there seems to be a reasonable safe zone regarding the reconstruction of offset and leg length.

Background

The Arthroplasty Pain Experience (APEX) studies are two randomised controlled trials in primary total hip (THR) and knee replacement (TKR) at a large UK orthopaedics centre. APEX investigated the effect of local anaesthetic wound infiltration (LAI), administered before wound closure, in addition to standard analgesia, on pain severity at 12 months. This abstract reports results of the within-trial economic evaluations.

Background

Prosthetic implants used in primary total hip replacements have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal); head sizes (small <36mm, large 36mm+); and fixation techniques (cemented, uncemented, hybrid, reverse hybrid), which influence prosthesis survival, patient quality of life, and healthcare costs. This study compared the lifetime cost-effectiveness of implants to determine the optimal choice for patients of different age and gender profiles.

Objectives

We used the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR) to investigate the risk of revision due to prosthetic joint infection (PJI) for patients undergoing primary and revision hip arthroplasty, the changes in risk over time, and the overall burden created by PJI.

Background

While many studies have investigated long-term outcomes after lower limb arthroplasty, rather less is known about the trajectory of short-term outcomes in the first post-operative year. It is difficult for a surgeon to know when, in terms of disease severity, it is best to operate, or to make an accurate prediction of the patient pattern of post-operative recovery. We explored the trajectory of change in pain and function following primary hip and knee arthroplasty and the influence of pre-operative self-reported symptoms on post-operative improvements.

Total hip replacement causes a short-term increase in the risk of mortality. It is important to quantify this and to identify modifiable risk factors so that the risk of post-operative mortality can be minimised. We performed a systematic review and critical evaluation of the current literature on the topic. We identified 32 studies published over the last 10 years which provide either 30-day or 90-day mortality data. We estimate the pooled incidence of mortality during the first 30 and 90 days following hip replacement to be 0.30% (95% CI 0.22 to 0.38) and 0.65% (95% CI 0.50 to 0.81), respectively. We found strong evidence of a temporal trend towards reducing mortality rates despite increasingly co-morbid patients. The risk factors for early mortality most commonly identified are increasing age, male gender and co-morbid conditions, particularly cardiovascular disease. Cardiovascular complications appear to have overtaken fatal pulmonary emboli as the leading cause of death after hip replacement.

Cite this article: Bone Joint Res 2014;3:175–82

The aim of this study was to determine the outcome of total hip arthroplasty, with regard to dislocation, at our unit.

1727 primary total joint arthroplasties and 305 revision total hip arthroplasties were performed between 1993 and 1996 at our unit. We followed up 1567 of the primary hip arthroplasties and 284 of the revision hip arthroplasties at 8 to 11 years post surgery. Patients were traced by postal questionnaire, telephone interview or examination of case notes of the deceased.

The dislocation rates by approach were: 23 out of 555 (4.1%) for the posterior approach, 0 out of 120 (0%) for the Omega approach and 30 out of 892 (3.4%) for the modified Hardinge approach.

58.5% of dislocations after primary total hip arthroplasty were recurrent. The mean number of dislocations per patient was 2.81.

8.1% of revision total hip arthroplasties suffered dislocation. 70% of these became recurrent. The mean number of dislocations per patient was 2.87. The vast majority of dislocations occur within 3 months of surgery.

To our knowledge this is the largest multisurgeon audit of dislocation after total hip arthroplasty published in the United Kingdom. The follow-up of 8 to 11 years is longer than most comparable studies.

The rate of deep infection following primary joint replacement has reduced to below 1%, but the cost remains high. The surgical team is the most important source of bacteria causing infection. All surgical gowns are susceptible to penetration by these organisms, which may then spread to the wound via the surgeon’s hands or contact with wet drapes without ever being airborne.

There is insufficient clinical data on the penetration of bacteria through surgical gowns, in part due to the difficulty of in vivo measurement. A simple new method was developed, using petri dishes filled with horse blood agar that were attached to the outside of the gown material. This was used to assess bacterial penetration through disposable spun-bonded polyester gowns and re-usable woven polyester gowns during normal use.

There was a significant difference between the two gown types when tested in the axilla (p < 0. 05), the groin (p < 0. 05) and the peri-anal region (p < 0. 01), with the disposable gowns performing to a higher standard.

Re-usable gowns demonstrated significant variation in penetrability. This is most likely to be due to the number of laundering and sterilisation cycles that they had undergone. Unless the continued satisfactory performance of multiple-use gowns can be guaranteed, they may be unsuitable for use in orthopaedic implant surgery.

The passage of bacteria through surgical drapes is a potential cause of wound infection. Previous studies have shown that liquids and human albumin penetrate certain types of drapes¹². We studied the passage of bacteria through seven different types of surgical drape and an operating tray. We also studied the effect of different wetting agents on the passage of bacteria through wet reusable woven drapes. Bacteria were grown on an overfilled whole horse blood agar plate. The plate was covered with the drape to be tested and a second agar plate was inverted and placed on the drape. After 30 minutes the second agar plate was removed, incubated and inspected for bacterial growth. The experiment was repeated removing the second plate at 60 minutes and then again at 90 minutes. The entire experiment was repeated for each drape and then for each wetting agent.

Bacteria easily penetrated all the woven reusable fabrics within 30 minutes. The disposable non-woven drapes proved to be impermeable up to 90 minutes, as did the operating tray.

Chlorhexidine and Povidone-Iodine were demonstrated to slow, but not stop the passage of bacteria through reusable woven drapes. Normal saline and human blood accelerated the passage of bacteria through reusable woven drapes. We recommend the use of non-woven disposable drapes or woven drapes with an impermeable operating tray, in all surgical cases.